A constant problem in the treatment of patients is their inability or unwillingness to swallow solid dosage forms such as tablets. This problem is most frequently encountered in children and the elderly. The problem is, however, not uncommon in healthy adults as well. Although this problem may seem innocuous or idiosyncratic, the fact remains that the inability or unwillingness of some people to take certain dosage forms can severely compromise the patient's compliance with a prescribed treatment protocol. Moreover, due to embarrassment, many patients are unwilling to tell their doctor of their problem so that the doctor can consider other drugs and/or alternate vehicles. Of course, such a lack of compliance can delay treatment or cure.
To overcome these problems, the pharmaceutical industry has developed syrups, elixirs, microcapsule containing slurries and unique tablets which dissolve in liquid prior to being consumed. Unfortunately, each of these dosage forms has its own limitations. Often, such dosage forms are more costly than traditional solid dosage forms such as simple tablets or capsules, both in terms of production, but also packaging.
From the consumer's side, alternate dosage forms also have significant disadvantages in terms of convenience. For example, effervescent tablets which are intended to be dissolved in a glass of liquid require the provision of a glass of liquid and a waiting period sufficient to allow the tablet to completely dissolve. Often, these dosage forms leave an objectionable scum which must be wiped out of the glass. Syrups and other liquid are often difficult or inconvenient to carry and inconvenient to take.
This problem is of course not limited to human patients. Animals are often no more willing to take pills than their human counterparts. Of course, it may be possible to mix tablets with an animal's food. However, certain dosage forms may require administration other than at regular feeding times. If a tablet could be devised which would be difficult for an animal to spit out, it might be easier to administer medication thereto.
One particularly innovative solution to these problems was described in Wehling et al., U.S. Pat. No. 5,178,878 which relates to certain effervescent dosage forms including microparticles. The effervescent dosage forms of Wehling et al. provide a significant advance over the art in that they provide an effervescent dosage form for direct oral administration. The dosage form is designed to disintegrate rapidly in the mouth releasing its microparticles as a slurry for ingestion. The dosage forms produced in accordance with Wehling et al. can be placed in the patients mouth and the effervescence contained therein will be activated by contact by the patient's saliva. The tablet will then disintegrate in a number of seconds.
This dosage form is particularly efficacious for administering fragile, rupturable microparticles and, in particular, rapid or immediate release microparticles for dosage forms which will be dosed, for example, every 4-6 hours. "Rapid release" is intended to mean that the microparticles will help mask the objectionable taste of a drug being administered, but once out of the mouth and in the digestive tract, the microparticle will provide as little an impediment as possible to the otherwise normal delivery profile of a drug contained therein. Such microparticles often tend to be broken when chewed. This causes the release of objectionable tasting drugs into the mouth of the patient. However, because the dosage form disintegrates so rapidly, the number of microparticles which can be crushed and thereby, the amount of material which can be released into the mouth is limited such that the sweeteners, flavorings and effervescent sensation of the disintegrating tablet can taste mask the objectionable taste.
K allstrand, et al., U.S. Pat. No. 4,994,260 relates to a pharmaceutical mixture. The mixture is used for the controlled release of a substance. According to K allstrand, et al., a liquid dosage form is produced using either a dry powder or microcapsules which are suspended in a solution of a release-controlling substance, also referred to as a "sink". Alternatively, it is possible to encapsulate the release-controlling substance, together with a drug, within an encapsulating shell. The release-controlling substance may include, inter alia, carbohydrates and carbohydrate-related compounds, disaccharides, monosaccharides, glycerol, glycol, glycosides of monosaccharides and substances derived from ethyleneglycol.
Boder et al., U.S. Pat. No. 5,126,151 relates to an encapsulation mixture. Boder et al. refers to the construction of gums and candies in oral dosage forms. According to Boder et al., microcapsules are produced including a core material which can be selected from a wide variety of materials including sweeteners, medicaments, drugs, flavoring agents and the like. These materials can be used, either singularly or in combination, in either a single or multiple part delivery system. That is, one or more of these materials may be present within one coating matrix or maybe separately coated by the matrix and employed alone or in combination in the final product. The resulting formulations are said to be able to provide a masking of unpleasant tasting drugs such as potassium chloride and the like, making consumption of the drug more appealing to the public. The dosage forms may be prepared in chewable tablet form.
Also of interest may be Schobel et al., U.S. Pat. No. 4,824,681, and Wei et al., U.S. Pat. No. 4,590,075. Encapsulated sweeteners have also been used to provide an extended release of sweetening in, for example, chewing gum, see for example European patent application EPO 87-810747 to Schobel et al. and in bakery products such as disclosed in WO 91-US9434 filed Dec. 17, 1991 to Redding et al.
The present invention provides an improvement over the art by advancing the pioneering technology described in the aforementioned Redding et al. patent.